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Koi

or more specifically (niɕikigoi, literally "brocaded carp"), are ornamental domesticated varieties of the common carpCyprinus carpio.

Origins

The common carp is widely believed to have originated from the Caspian Sea with natural habitat surrounding the North, Baltic, Mediterranean, Black, Azov, Caspian and Aral Sea basins. The common carp, as a food fish with the ability to survive and adapt to many different climates and waterways, was bartered and spread to many different areas, including North America, Africa, Europe, and Asia. Wild populations of the common carp now exist in those four continents and South America.

Natural color mutations of these carp would have occurred across all populations. Historical records indicate that carp with color mutations were found in China. However, the earliest records of carp with distinct colors kept for selective breeding, true Nishikigoi, have been found in Japan. Depictions of carp or 'koi' with different color variations have been found on 18th century Japanese drawings and paintings. The ornamental cultivation of carp originated in the Niigata region of Japan during the JapaneseEdo Period.

Etymology

The word "koi" comes from Japanese, simply meaning "carp." It includes both the dull grey fish and the brightly colored varieties. A homophone of koi means "love, affection" and koi are therefore symbols of love and friendship in Japan: a good example is the short story Koi-san by Mukoda Kuniko.

History

Koi breeding originated in the 18th century in the Niigata prefecture of Japan. Farmers working the rice fields would notice that some carp were more brightly colored than others, capture them, and raise them. By the 20th century, a number of color patterns had been established, most notably the red-and-white Kohaku. The outside world did not become aware of the degree of development until 1914, when the Niigata koi were exhibited in the annual exposition in Tokyo. At that point, interest in koi exploded throughout Japan. The hobby of keeping koi spread worldwide after plastic bags and shipping of koi became both fast and safe for the fish. These factors enabled koi to be shipped worldwide with low mortality rates. Koi are now commonly sold in most pet stores, with higher-quality fish available from specialist dealers.

Koi varieties are distinguished by coloration, patterning, and scalation. Ghost koi, developed in the 1980s are metallic hybrids of wild carp and Ogon koi and are not considered true Nishikigoi. Butterfly koi, Longfin koi, or Dragon Carp were also developed in the 1980s and are notable for their long and flowing fins. They are actually hybrids with Asian carp and, like Ghost koi, are not considered true Nishikigoi.

Varieties

Koi have many different colors. Some of the major colors are white, black, red, yellow, blue, and cream.

While possible variations are limitless, breeders have identified and named a number of specific categories. The most popular category is Gosanke. The Gosanke category is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties. The Japanese breeders have many generations of knowledge and experience when it comes to breeding and raising Nishikigoi. They know which ones will be worth hundreds of dollars and which ones will be worth thousands of dollars.

The major named varieties include:

Kohaku - a white-skinned Koi, with a red pattern

Taisho Sanshoku (Sanke) - a white-skinned Koi with a red and black pattern

Showa Sanshoku (Showa) - a black-skinned Koi with a red and white pattern

Tancho - Any koi with the only red being in a circle on its forehead. The fish can be a Tancho Showa, Tancho Sanke, or even Tancho Goshiki

Asagi - a Koi with light blue scales on its top and red scales on its bottom

Shusui - the partially scaled version of an Asagi

Bekko - a white, red, or yellow-skinned Koi with a black pattern

Utsurimono - a black Koi with a red, white, or yellow pattern

Goshiki - a mostly black Koi with red, white, brown, and blue accents

Ogon - a Koi that is one solid color, can be regular or metallic; known colors - red, orange, platinum, yellow and cream

Kin Gin Rin - a Koi with shiny scales. The name translates into English as "Gold Silver Scales" There are also Gin Rin versions of almost any other type of koi.

Kawarimono (kawarigoi) - Miscellaneous types of Koi

Doitsu-goi - German Carp

Koromo - Koi with areas of blue-edged scales aligned neatly

Hikari-Moyomono - Koi with coloured patterns over a metallic base, and koi in two metallic colours

Keeping

The common carp is a hardy fish, and koi retain that durability. Koi are cold-water fish, but benefit from being kept in the 15-25 degrees C range and do not react well to long cold winter temperatures, their immune system 'turning off' below 10 degrees C. Koi ponds have a meter or more of depth in areas of the world that become warm during the summer. In areas that have harsh winters, ponds that are a minimum of 1.5 meters (4 1/2 feet) are most common.

Koi's bright colors put them at a severe disadvantage against predators; a white-skinned Kohaku is a visual dinner bell against the dark green of a pond. Herons, kingfishers, raccoons, cats, foxes, and badgers are all capable of emptying a pond of its fish. A well-designed outdoor pond will have areas too deep for herons to stand in, overhangs high enough above the water that mammals can't reach in, and shade trees overhead to block the view of aerial passers-by. It may prove necessary to string nets or wires above the surface. A pond usually includes a pump and filtration system to keep the water clear.

Koi are an omnivorous fish and will often eat a wide variety of foods, including peas, lettuce, and watermelons. Koi food is designed not only to be nutritionally balanced, but also to float so as to encourage them to come to the surface. When they are eating, it is possible to check koi for parasites and ulcers. Koi will recognize the person feeding them and gather around him or her at feeding times. They can be trained to take food from one's hand. In the winter, their digestive system slows nearly to a halt, and they eat very little, perhaps no more than nibbles of algae from the bottom. Their appetite will not come back until the water becomes warm in the spring. When the temperature drops below 50 degrees Fahrenheit (10 °C), feeding, particularly with protein, is halted or the food can go rancid in their stomach, causing sickness.

Koi can live for decades. One famous scarlet koi, named "Hanako" (c. 1751 – July 7, 1977) was owned by several individuals, the last of which was Dr. Komei Koshihara. Hanako was reportedly 226 years old upon her death. Her age was determined by removing one of her scales and examining it extensively in 1966. She is (to date) the longest-lived koi fish ever recorded.

Culturing

Like most fish, koi reproduce through spawning in which a female lays a vast number of eggs and one or more males fertilize them. Nurturing the resulting offspring (referred to as "fry") is a tricky and tedious job, usually done only by professionals. Although a koi breeder may carefully select the parents they wish based on their desired characteristics, the resulting fry will nonetheless exhibit a wide range of color and quality.

Unlike a purebred dog or cat, even the finest champion-grade koi will produce literally thousands of unacceptable, unrecognizable, or even genetically defective offspring in a single spawning. These (and hundreds of marginal offspring) are culled at various stages based on the breeder's expert eye and closely guarded techniques.

Culled fry are usually destroyed (perhaps fed to other fish) and older culls are often sold as lower-grade "pond-quality" koi within their first year (also called "Tosai") at 3"–6" long. The semi-randomized result of the koi's reproductive process is both a blessing and a curse. While it requires diligent oversight to narrow down the favorable result that the breeder wanted all along, it also made possible the gradual transformation of wild river carp into the exquisite art form seen in modern nishikigoi.

In the wild

Koi have been accidentally or deliberately released into the wild in every continent except Antarctica. They greatly increase the turbidity of the water because they are constantly stirring up the substrate. This makes waterways unattractive, reduces the abundance of aquatic plants, and can render the water unsuitable for swimming or drinking even by livestock. In some countries, koi have caused so much damage to waterways that vast amounts of money and effort have been spent trying to eradicate them, largely unsuccessfully.